Concern with the health hazards associated with industrial exposure to materials, in particular vinyl chloride, has caused the allowable concentration of vinyl chloride to be reduced substantially from the previous standards to levels in air of one part vinyl chloride to every million parts of air, averaged over an eight-hour period. Levels of vinyl chloride in the atmosphere may exceed one part per million for short periods; however, it must average no more than five parts per million for any fifteen minute period over an eight-hour span.
Various methods for reducing vinyl chloride emissions from PVC manufacturing and fabrication plants have been proposed. These include the adsorption of the vinyl chloride monomer from vent gases on activated charcoal with the monomer regenerated with steam and the vinyl chloride re-introduced into the process. Other control techniques include thermal decomposition of the monomer or solvent scrubbing.